Control system for elevators



Oct. 2, 1962 R. MOSER ETAL CONTROL SYSTEM FOR ELEVATORS 3 Sheets-Sheet 1 Filed April 8, 1960 Fig.

R. MOSER ETAL CONTROL SYSTEM FOR ELEVATORS Oct. 2, 1962 3 Sheets-Sheet 2 Filed April 8, 1960 1 m m RST. HO T5 2 ..l||: R W H w L mm m a 5 D G KK K Q W 6 5 W a 11. J. 6 m w 2 L w S w J 2 I I'll I 1 2 T ,8 US \U K H 5 H x R 4 5 U 9 m a K 5 4. w 6 6 4 m? I n 3 6 m B .8 M g 2 3 I r T 6 T a 4 3 K F OJIL C H 3 D Y 0 A ma Lu 3 7 5 w 3 1 V w w M 1962 R. MOSER ETAL CONTROL SYSTEM FOR ELEVATORS 3 Sheets-Sheet 3 Filed April 8, 1960 Fig. 4

1 w 3 E I QIJ 8 4 5 6 2 V nv 8 8 up K K R 2 2 3 5 K m H M 1 H R R R R R W 2 2 2 2 2 K K K K K 2 3 4 M S S S J J .J J J K K K K H a 8 1 2 6 V r W R 71w 2 2 O K K 3 L G W O\ 3 4 2 O S S S V v U w R R R R R R RU2 -MM United States Patent Oflice 3,056,470 Patented Oct. 2, 1962 3,056,470 CONTROL SYSTEM FOR ELEVATORS Richard Moser, Dietikon, Zurich, and Marcel Etter,

Carouge-Geueva, Switzerland, assignors to Schweizerische Wagonsund Aufzugefabrik A.-G. Schliereu- Zurich, Schlieren, Zurich, Switzerland Filed Apr. 8, H60, Ser. No. 21,010 Claims priority, application Switzerland Apr. 9, 1959 8 Claims. (Cl. 18731) The present invention relates to control systems for elevators having contactless generator elements incorporated in the safety circuit in order to prevent the operation of the elevator when the elevator is not safeguarded.

The safety circuit of an elevator must not permit movement of the elevator cab until all doors are closed and locked and only if the safety contacts such as stop button contact, safety griup contact, slack rope contact, etc. are actuated, i.e. when the whole control system is safeguarded.

It is an object of the present invention to provide such a safety system in which the whole control system is brought into the safe condition, i.e. the elevator has to be shut down if an element of the safety circuit fails on account of a mechanical trouble. Advantageously the presence of a safety signal is chosen as a sign of the safe condition.

The invention contemplates a control system for elevators having a safety circuit which meets the abovementioned requirements while the advantages of the reliability of operation, short switching time and reduced maintenance of the contactless generator elements are guaranteed.

According to the invention a control system for elevators is provided in which the generator elements comprise series-connected magnetically saturable cores provided with at least one winding and influenced by at least one magnet, the mutually associated cores and magnets moving relatively to each other, and the signal, corresponding to the saturation or desaturation of any core and produced in the winding thereof or controlled by said winding, influences the output signal of the safety circuit and thus the control of the elevator.

A preferred embodiment of our invention is illustrated in the accompanying drawings, wherein FIG. 1 shows an elevation of a single shaftway of an elevator with a generator element for the closing control of the shaftway door and the door lock,

FIG. 2 illustrates the shaftway door lock with the generator element for the control of the door safety bolt and FIGS. 3 and 4 show a circuit diagram of an elevator control system.

Referring to FIG. 1 the shaftway of a shaftway door is generally indicated by and the door frame by 11. In order to sense the closed position of the shaftway 10 the door is provided with a generator element KT. This generator element consists of a magnet 57 preferably a permanent magnet fixed in the shaftway 10 and actuating a magnetically saturable core 52 mounted in the door frame 11. This core 52 is provided with a winding 12. When the shaftway door is closed the magnet 57 saturates the core 52, whereas the core 52 is desaturated with the door open. Thus, an alternating current applied to the winding 12 may flow through the winding with the door closed, whereas with the door open the alternating current is interrupted in the winding 12 on account of the throttle effect of the latter.

The door frame 11 also contains a lock 13 featu ing a roller lever 14. The lock 13 is represented in FIG. 2 in a larger scale and comprises a housing 15 of magnetically non-conductive material, the housing 15 having in a guiding manner a safety bolt 16. This safety bolt 16 cooperates with a bolt lever 17 actuated by the roller lever 14. With the door closed the safety bolt 16 enters the shaftway 10 and prevents an unintentional opening of the door. A generator element KV is disposed in the housing 15 and comprises a magnetically saturable core 70 fixed to the housing and provided with two windings. The saturable core 70 is influenced on the one hand by a magnet 75, preferably a permanent magnet, fixed by means of an unequal-leg angle 18 of non-magnetisable material and on the other hand by a magnet 80, preferably a permanent magnet, joined by means of an intermediate piece 19 of non-magnetisable material to the safety bolt 16. With the door locked both magnets and act on the core 70. The polarities of these magnets are chosen so that the lines of magnetic flux neutralize each other, thus desaturating the core 70. As soon as the safety bolt 16 is brought into the unlocked position, only the magnet 75 can act upon the core 70 thus provoking a saturation-of the latter. With the door locked an alternating voltage applied to the primary winding is transmitted to the secondary winding, whereas with the door unlocked such a transmission is not able to occur on account of the saturation of the core 70.

In FIG. 3 showing a simplified wiring diagram a drive motor 30 acts upon a gearbox 32 by the intermediary of a brake 31 comprising a brake disk, brake shoe and brake magnet MB. A drive pulley 33 is mounted on the slowly rotating shaft of the gearbox 32 and carries wire ropes 34, one end of which supports a cab 35 and the other end of which carries a counterweight 36. Call buttons DC and a stop button DH are provided in the cab 35. A guide rail 37 is fixed to the cab for actuating shaftway switches JS15 one of each is mounted in an appropriate position at each landing serviced by the elevator. Moreover, a locking magnet MV is mounted on the cab cooperating with a movable guide rail 38 which actuates the roller lever 14 and the door lock 13 connected with the roller lever 14.

The motor 30 is fed from a three-phase power source having lines R, S and T by means of power contactors, for example reversing contactors RUI and RU2. The primary winding of a transformer Trl is coupled to the lines S and T. The ciphers of the wiring diagram for an elevator servicing five landings have the following signification:

KRU-

Contacts of the contactors.

Contacts of the precontrol relay.

Generator element for the locking control of the doors.

RRl-S Floor relays.

RUl Reversing switch for travelling up. RU2 Reversing switch for travelling down. RV Precontrol relay.

One secondary winding 50 of the transformer Trl is coupled with a rectifier GL1, the positive output of which is connected with a positive common conductor 1000 and the negative output of which is connected with a negative common conductor 101 of the elevator control system.

Another secondary winding 51 of the transformer Tr1 is connected to lines 65 and 66. The line 66 is coupled to a winding 12 of a first magnetically saturable element KTl of a first part of the safety circuit comprising elements KTl-S for the closing control of the door each door having one of these elements. With the doors closed the cores 52-56 of the permanent magnets 57-61 are saturated. Each core 52-56 is provided with a winding 12 all these windings being connected in series. The end of the winding of the last core 56 is coupled with the input of a push-pull transistor amplifier 62 consisting of an input transformer "[12, of transistors 63, 64 and of an output transformer Tr3. The other input of the amplifier 62 is hooked up to the line 65. In installations with a big number of series-connected elements KT it is an advantage to connect an end impedance for the first part of the safety circuit in parallel with the inputs of the amplifier 62.

The end outputs of the secondary Winding of the transformer Tr2 are coupled to the base of the transistors 63 and 64 respectively. The middle output of the secondary winding of the transformer T12 is connected with the emitters of the transistors 63 and 64 and with the positive common line 1000. The collectors of the transistors 63 and 64 are connected to an end each of the primary winding of the transformer Tr3. The primary winding of this transformer is fed in the middle from the line 101 through a second part of the safety circuit comprising a safety grip contact K] and a stop button DH. The secondary winding of the transformer Tr3 is connected with the inputs of a rectifier GL2. The positive output of the rectifier GL2 is hooked up to the line 1000, whereas the negative output serves as an omnibus line 130. Between the omnibus line 130 and the line 1000 the call button and shaftway circuit is connected.

Referring now to FIG. 4 the lines 65 and 66 are coupled with the primary winding of the first generator element KVI of a third part of the safety circuit comprising a generator element KVl-S for each door lock for the locking control of the door, the line 65 being provided with a. limit resistance 67. The generator elements KVl-S comprise magnetically saturable cores 7074 each being surrounded by two windings. The windings are so connected that the secondary winding of the preceding generator element is feeding the primary winding'of the following generator element. Each core 70-74 is acted upon by a fixed magnet 75-79 each and by a movable magnet 8034 mounted on the safety bolt 16. The secondary winding of the core 74 of the last generator element KV is connected with the inputs of a two-stage push-pull transistor amplifier 85.

The first stage of the amplifier 85 consists 'of an input transformer Tr l, transistors 86 and 87 and the primary Winding of a transformer Tr5. A second stage comprises the secondary winding of the transformer Tr5, transistors 88 and 89 and an output transformer "D6. The first and the second stage of the amplifier 85 is connected analogously as already has been described with respect to the amplifier 62. The middle points of the secondary windings of the transformers Trd and T are connected with the line 1000. The first stage is fed from the omnibus line 130 through the middle point of the primary winding of the transformer TrS, and the second stage is fed from the line 101 through the middle point of the primary winding of the output transformer Tr6.

The outputs of the amplifier 85 lead to a rectifier GL3. The positive output of the rectifier GL3 leads to the line 1000 whereas the negative output energizes through a line 90 and the contacts KRV and KRU the coils of the contactors RU1 and RUZ.

According to the diagram of FIGS. 3 and 4 the cab is stopped in the third landing as the contact K183 of the shaftway switch 183 occupies the middle position. The core 72 of the safety circuit is saturated, because the safety bolt 16 of the door lock 13 of the third landing is unlocked, the locking magnet MV being currentless and the movable guide rails having actuated the roller lever in the unlocking sense.

A DC. voltage is applied to the two lines 101 and 1000, and an A.C. voltage is applied to the lines 65 and 66. As all doors are closed and the cores 5256 are saturated. Therefore, the windings of the cores 5256 being connected in series in the first part of the safety circuit, let pass the A.C. current of the lines 65 and 66 thus energizing the primary winding of the input transformer T12 of the amplifier 62. This amplifier 62 operating according to the push-pull principle, amplifies the AC. voltage which is applied to the rectifier GL2.

As already mentioned above it is necessary with a safety circuit of an elevator control system that it is brought into a safe state when troubles occur, i.e. the elevator control circuit must be interrupted. It is known that transistors are subject, though only rarely, to short-circuits. If such a short-circuit occurs in the transistor 63 it will lose its control capacity in the base-emitter-circuit. The DC. current in the circuit comprising line 101, contact K], stop button DH, secondary winding of the transformer Tr3, collector of the transistor 63, emitter of transistor 63 and line 1000 increases. On the other hand the AC. signal at the output of the amplifier 62 decreases so that it is no longer strong enough to actuate the ele vator control.

When a magnet breaks down, for example, magnet 57 mounted in the shaftway 10, in consequence of a loosening of its fixing, the elevator control is interrupted, because when this magnet is not provided the core -52 is desaturized, ensuing in an interruption of the A.C. current flowing through the windings 12 of the magnet 57.

In the illustrated example the third part of the safety circuit with the generator elements KVL-S is interrupted, as the cab is stopped at the third landing and the cab door is unlocked resulting in a saturation of the core 72. But the saturated core prevents a transformatory transmission of the A.C. voltage carried by the line 65 and 66. The contactor coils RU1 and RU2 cannot be energized on account of the interruption of the safety circuit and the cab can only be put into motion, if all doors are locked.

An example of an elevator trip will be described in the following: It is supposed that the shaftway call button DA1 is pushed. All doors being closed the generator elements KT 1-5 are saturated. The AC. voltage applied to the lines 65 and 66 flow through the windings of the cores 52-56 so that a DC. voltage is flowing between the lines 130 and 1000. As soon as the shaftway call button DA1 is pushed, a DC. current flows from the omnibus line 130 (FIG. 4) through the cont-act of the brake magnet KBMcall button DA1, and the relay RS1 is operated. This results in the closing of contact K2RS1, and through the contacts K181 and K2RV1 the relay RV2 is operated. The self-holding circuit of the floor relay RS1 is closed through the intermediary of the contacts K1RV2 and KlRSl. By energizing the relay RVZ the contact K3RV2 is closed thus energizing the locking magnet MV. The movable guide rail 33 is retracted and the safety bolt 16 locks the door of the third floor. Now the magnet 82 influences the core 72 and desaturates it. The A.C. current applied to the third part of the safety circuit is able to flow through the safety chain is amplified in the amplifier and is converted into a DC. current in the rectifier GL3. This D.C. current operates the contactor RU2 by the intermediary of line 90, contact K4RV2 and contact K2RU1. By means of contact KlRUZ the brake magnet is energized, and the brake 31 is released. The motor 30 puts the cab 35 into motion.

As soon as the cab 35 approaches the first floor the shaftway switch I S1 is actuated by the guide rail 37. Contact KJSI opens, relay RVZ and contactor RU2 are deenergized, the brake magnet becomes currentless and the brake 31 is operated. The locking magnet MV is deenergized, and the movable guide rail 38 unlocks the door lock 13.

In the described example the throttle principle was considered to be the switching criterium of the generator elements in the first part of the safety circuit, and the transformatory principle for the third part. But in most cases either one or the other one will be used in both parts of the safety circuit. It will be an advantage to .5 unite both parts in a safety chain to take over the reference signs for the elevator control at the required points of the safety chain.

Moreover, according to the described example the second part of the safety circuit with the safety contacts DH and K] was included in the DC. supply of the amplifier 62. All safety contacts, such as stop button, safety grip contact, regulator contact, etc. also can be included in the first part of the safety circuit in form of contactless, saturable and series-connected elements.

According to FIGS. 3 and 4 the output signals of the first and third part of the safety circuit were first amplified and rectified, and only afterwards they influenced the elevator control provided with relays. However, should these output signals influence an elevator control provided with magnetic gate elements, for example, no amplification would be needed. If the generator elements are properly dimensioned, the output signal of the safety circuit may be used for the direct actuation of a power contactor.

While a preferred embodiment has been illustrated and described it will be obvious from the foregoing description that the control system is susceptible of considerable modification without departing from the essential features or sacrificing any of the advantages thereof as come with in the scope of the following claims.

What we claim is:

1. A control system for elevators having a safety circuit and contactless generator elements therein for selectively preventing movement of the elevator, said generator element comprising a plurality of magnetic cores of saturable material in series connection, at least one Winding on each of said cores, at least one magnet, said magnet and cores being movable with respect to one another, said magnet saturating said cores to a determinable degree upon relative movement therebetween, said safety circuit being responsive to the degree of saturation of said core to control movement of the elevator.

2. A control system as claimed in claim 1 comprising a source of A.C. voltage connected to at least one of said windings, said voltage flowing through the one winding, with said corresponding core saturated.

3. A control system according to claim 2 comprising at least one amplifier and rectifier connected to said cores for receiving the A.C. voltage selectively flowing therein.

4. A control system as claimed in claim 1 comprising a primary and secondary winding on at least one of said cores of saturable material, said elevator including a door movable with respect to said cores, means for locking said door, a fixed magnet operatively coupled to said one core and constantly saturating the same, a magnet of opposite polarity of that of said fixed magnet and coupled to said movable door and said means, the last said magnet being adjacent said fixed magnet with said door closed and locked to counteract said fixed magnet, thereby desaturating said one core.

5. A control system as claimed in claim 4 comprising a plurality of stations, at least one core at each of said stations, the secondary windings of said cores being successively connected to the primary windings of cores at adjacent stations to feed the same.

6. A control system as claimed in claim 1 comprising a source of A.C. voltage connected to at least one of said windings, said voltage flowing through the one winding with said corresponding core being saturated, said elevator including a door, means for locking said door, said generator elements being operatively coupled to said door so that said core is saturated with said door closed and locked and desaturated with the door open and unlocked.

7. A control system as claimed in claim 1 comprising a winding on each said core, a first transformer including primary and secondary windings, the windings on said core being connected to the primary winding of the first transformer, said secondary winding having end outputs and a middle output, a transistor coupled to each of the end outputs of said secondary Winding, said transistors having emitters connected to the middle output of said transformer, a positive common line, said middle output being connected to said positive common line, a second transformer including a primary winding having end inputs and a middle input, said transistors having collectors connected to the end inputs of said primary winding of the second transformer, a negative common line, the middle input of said second transformer being connected to said negative common line, means for controlling said elevator, a rectifier, said secondary transformer including a secondary winding coupled to said rectifier, the rectifier being connected to the means for controlling the elevator, said safety circuit including an amplifier, said rectifier being connected to said amplifier.

8. A control system as claimed in claim 1 comprising first and second windings on said cores operatively coupled to constitute a transformer, said cores being sequentially arranged, whereby the secondary windings of said cores are sequentially connected to the primary windings of adjacent cores, a first transformer including primary and secondary windings, the last sequential secondary winding of the cores being connected to the primary winding of the first transformer, said secondary winding of the first transformer having end outputs and a middle ouptut, a transistor coupled to each of the end outputs of said secondary winding of the first transformer, said transistors having emitters connected to the middle output of the first transformer, a positive common line, said middle output being connected to said positive common line, a second transformer including primary and secondary windings, said primary winding of said second transformer including end inputs and a middle input, said transistors having collectors connected to the end inputs of the primary winding of the second transformer, a rectifier, said rectifier being connected to the middle input of said primary winding of the second transformer, the secondary winding of the second transformer having end outputs and a middle output, a second pair of transistors, each being coupled to the end outputs of said secondary windings of the second transformer, said second transistors having emitters connected to the middle output of the secondary winding of the second transformer and to the positive common line, said second transistors having collectors, a third transformer including a primary winding having end inputs and a middle input, a negative common line, said collectors of the second transistors being connected to the input ends of the third transformer, said middle input of the primary winding of the third transformer being connected to the negative common line, means for controlling said elevator, said third transformer including a secondary winding connected to the last said means to energize the same.

References Cited in the file of this patent UNITED STATES PATENTS 1,344,430 Wigmore et al June 22, 1920 1,453,073 Laureyns Apr. 23, 1923 2,624,792 Fruh Jan. 6, 1953 2,877,361 Chase Mar. 10, 1959 2,989,148 Moser June 20, 1961 FOREIGN PATENTS 691,555 Great Britain May 13, 1953 612,820 Canada Jan. 17, 1961 

